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Carbon quantum dots/Bi_(4)O_(5)Br_(2) photocatalyst with enhanced photodynamic therapy:killing of lung cancer(A549)cells in vitro

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Rare Metals 2022年第1期41卷 132-143页

作者： Bing He Hai-Yan Jin Ya-wen Wang Cai-Mei Fan Yun-Fang Wang Xiao-Chao Zhang Jian-Xin liu Rui Li jue-wen liu College of Chemistry and Chemical Engineering Taiyuan University of TechnologyTaiyuan 030024China Department of Chemistry University of WaterlooWaterlooON N2L 3G1Canada

Inorganic photocatalysts have been regarded as a promising candidate in the domain of tumor photodynamic therapy(PDT)due to their inspirational photocatalytic *** this study,a Bi_(4)O_(5)Br_(2)photocatalyst was synthesized and it exhibited effective photo-killing activity of A549 cells(a human lung carcinoma epithelial cell line)in *** this basis,we modified Bi_(4)O_(5)Br_(2)with carbon quantum dots(CQDs)via a hydrolysis method at room temperature,which resulted in an improved photo-killing effect of Bi_(4)O_(5)Br_(2)to A549 *** samples and the interaction between samples and cells were fully *** has been found that the loading of CQDs on Bi_(4)O_(5)Br_(2)can reduce the hydration ratio,increase the cellular uptake and improve the photogenerated reactive oxygen species(ROS)as compared with pristine Bi_(4)O_(5)Br_(2).Electron spin resonance(ESR)analysis and radical-trapping experiments manifested that the ROS contributed to PDT may be·O^(2-)and ·*** study may provide a useful strategy to ameliorate the penetrability,cell compatibility and PDT effect upon cancer cells of other inorganic photocatalysts.

关键词： CQDs/Bi_(4)O_(5)Br_(2) Photocatalyst PDT A549 cell Reactive oxygen species

Detachment-Independent Cationic-Dipeptide Beacons:Reduced False-Negative Signal and Accelerated Fluorescent Lighting in Cell Imaging

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Journal of Analysis and Testing 2022年第1期6卷 19-26页

作者： Guang-Wei Fu Guo-Yan Luo Xiao-Xuan Li Zhen Zou Yan-Li Lei Zhi-He Qing jue-wen liu Rong-Hua Yang Hunan Provincial Key Laboratory of Cytochemistry School of Chemistry and Chemical EngineeringChangsha University of Science and TechnologyChangsha 410114China College of Chemistry and Chemical Engineering Hunan Normal UniversityChangsha 410081China Department of Chemistry Waterloo Institute for NanotechnologyUniversity of WaterlooWaterlooON N2L 3G1Canada

Nanocarriers have been developed to deliver DNA probes into cells for imaging analysis and improving their nuclease ***,we found obvious lowered sensitivity and even false-negative results in the traditional DNA detachment-dependent fluorescent lighting ***,we developed a detachment-independent fluorescent lighting mechanism integrated with cationic dipeptide nanoparticles(CDNs).CDNs displayed little quenching effect on fluorophores labeled on probes and improved the nuclease resistance of *** contrast to the traditional beacon,the fluorescence lighting was significantly accelerated without the need of desorption of the recognition products from the nanosurface,avoiding false-negative results from non-specific conformational *** work will open up new thoughts to improve the sensing performance of DNA probes in cell imaging,such as speed and sensitivity.

关键词： Cationic dipeptide nanoparticles DNA probe False-negative signal Fluorescence Cell imaging

Evaluation of COVID-19 outbreak prevention and control in Beijing using the emergency management theory

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Fundamental Research 2024年第3期4卷 671-677页

作者： Yu Wu jue liu Min liu School of Public Health Peking UniversityBeijing 100191China

On April 29,2020,China entered a normalization stage of prevention and *** December 2021,more than 40 outbreaks had occurred in China,which reflected the shortcomings of the pandemic prevention and control measures in China at that *** the capital city of China,Beijing faces more pressure in epidemic prevention and *** used the COVID-19 cluster containment evaluation indicators to determine the effects of prevention and control measures on four COVID-19 outbreaks in *** considering the specificity and operability of evaluation indicators and the availability of evaluation data,the evaluation system in our study consisted of six dimensions:epidemic prevention and control effect,discovery and detection ability,precision prevention and control capability,public protection effect,medical treatment and nosocomial infection prevention and control ability,and information release and public opinion response *** composite scores of the prevention and control effects of the Xinfadi,Shunyi,Daxing,and Ejina Banner–associated COVID-19 outbreaks in Beijing were 62,82,87,and 76,*** the six dimensions,the epidemic prevention and control effect,discovery and detection ability,precision prevention and control capability,and public protection effect scores for the Xinfadi outbreak were lower than those for the Shunyi,Daxing and Ejina Banner–associated *** medical treatment and nosocomial infection prevention and control ability scores for the outbreak associated with Ejina Banner were lower than those for the Xinfadi,Shunyi,and Daxing *** managing cluster outbreaks,Beijing was able to detect index cases early enough to reduce the scale and duration of the outbreak and consistently release official information to reduce public panic,standardize the management of centralized quarantine sites to prevent cross-infection,adhere to the“dynamic COVID‐zero”strategy to accurately prevent and control outbreaks,reduce the societa

关键词： Cluster outbreaks COVID-19 Prevention and control Evaluation Beijing

Superconvergence of Direct Discontinuous Galerkin Methods:Eigen-structure Analysis Based on Fourier Approach

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Communications on Applied Mathematics and Computation 2024年第1期6卷 257-278页

作者： Xuechun liu Haijin Wang jue Yan Xinghui Zhong School of Mathematical Sciences Zhejiang UniversityHangzhou310027ZhejiangChina School of Science Nanjing University of Posts and TelecommunicationsNanjing210023JiangsuChina Department of Mathematics Iowa State UniversityAmes50011IAUSA

This paper investigates superconvergence properties of the direct discontinuous Galerkin(DDG)method with interface corrections and the symmetric DDG method for diffusion *** apply the Fourier analysis technique to symbolically compute eigenvalues and eigenvectors of the amplification matrices for both DDG methods with different coefficient settings in the numerical *** on the eigen-structure analysis,we carry out error estimates of the DDG solutions,which can be decomposed into three parts:(i)dissipation errors of the physically relevant eigenvalue,which grow linearly with the time and are of order 2k for P^(k)(k=2,3)approximations;(ii)projection error from a special projection of the exact solution,which is decreasing over the time and is related to the eigenvector corresponding to the physically relevant eigenvalue;(iii)dissipative errors of non-physically relevant eigenvalues,which decay exponentially with respect to the spatial mesh sizeΔ*** observe that the errors are sensitive to the choice of the numerical flux coefficient for even degree P^(2)approximations,but are not for odd degree P^(3)*** experiments are provided to verify the theoretical results.

关键词： Direct discontinuous Galerkin(DDG)method with interface correction Symmetric DDG method Superconvergence Fourier analysis Eigen-structure

Enhancing XRF sensor-based sorting of porphyritic copper ore using particle swarm optimization-support vector machine(PSO-SVM)algorithm

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International Journal of Mining Science and Technology 2024年第4期34卷 545-556页

作者： Zhengyu liu jue Kou Zengxin Yan Peilong Wang Chang liu Chunbao Sun Anlin Shao Bern Klein School of Civil and Resources Engineering University of Science and TechnologyBeijing 100083China Institute of Minerals Research University of Science and TechnologyBeijing 100083China State Key Laboratory of Mineral Processing Beijing 102628China Ansteel Group Mining Co.Ltd. Anshan 114000China Norman B.Keevil Institute of Mining Engineering University of British ColumbiaVancouverBC V6T 1Z4Canada

X-ray fluorescence(XRF)sensor-based ore sorting enables efficient beneficiation of heterogeneous ores,while intraparticle heterogeneity can cause significant grade detection errors,leading to misclassifications and hindering widespread technology *** classification models are crucial to determine if actual grade exceeds the sorting threshold using localized XRF *** studies mainly used linear regression(LR)algorithms including simple linear regression(SLR),multivariable linear regression(MLR),and multivariable linear regression with interaction(MLRI)but often fell short attaining satisfactory *** study employed the particle swarm optimization support vector machine(PSO-SVM)algorithm for sorting porphyritic copper ore ***-scale results showed PSO-SVM out-performed LR and raw data(RD)models and the significant interaction effects among input features was *** poor input data quality,PSO-SVM demonstrated exceptional ***-scale sorting achieved 93.0%accuracy,0.24%grade increase,84.94%recovery rate,57.02%discard rate,and a remarkable 39.62 yuan/t net smelter return(NSR)increase compared to no *** improvements were achieved by the PSO-SVM model with optimized input combinations and highest data quality(T=10,T is XRF testing times).The unsuitability of LR methods for XRF sensor-based sorting of investigated sample is *** element selection and mineral association analysis elucidate element importance and influence mechanisms.

关键词： XRF sensor-based sorting PSO-SVM algorithm Copper ore pebble Receiver operating curve(ROC) Net smelter return(NSR)

Effect of Pre-strain on Microstructure and Stamping Performance of High-strength Low-alloy Steel

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Journal of Wuhan University of Technology(Materials Science) 2024年第3期39卷 774-780页

作者：刘坡 wen Zhicheng liu Zheng 许峰 School of Mechanical Engineering Guilin University of Aerospace TechnologyGuilin 541004China School of Automotive Engineer-ing Changshu Institute of TechnologyChangshu 215500China

In this study,pre-strain ranging from 0 to 0.12 was applied through uniaxial tension on high-strength low-alloy(HSLA)specimens with four kinds of grain *** of pre-strain and grain size on me-chanical property was investigated through tensile *** of the pre-strained and tensile tested samples were analyzed,*** 30.8°v-bending and following flattening,as well as Erichson cupping tests,were performed on the pre-strained *** show the elongation ratio of grain and dislocation density increases with *** platform is removed when pre-strain is larger than 0.06 while yielding plateau period decreases with pre-strain less than 0.06 due to reduction of pinning *** 30.8°v-bending and the following flattening tests are successfully accomplished on all the pre-strained samples with different grain *** in grain size,along with increase in pre-strain,causes increase in strength and decrease in elongation rate as well as cupping ***-strain causes very slight effect on bending ability,much less than that on mechanical property and cupping test *** impact of the pre-strain and grain size on HSLA steel deformability is inconspicuous.

关键词： strain hardening dislocation texture bending erichson cupping test

Thermodynamic nature of black holes in coexistence region

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Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 27-32页

作者： Shao-wen Wei Yu-Xiao liu Lanzhou Center for Theoretical Physics Key Laboratory of Theoretical Physics of Gansu Provinceand Key Laboratory of Quantum Theory and Applications of Mo ELanzhou UniversityLanzhou 730000China Institute of Theoretical Physics&Research Center of Gravitation Lanzhou UniversityLanzhou 730000China

Studying the system state of coexistence regions will peek into to reveal microscopic interactions between different phases of a thermodynamic ***,there is no effective method to study thermodynamic nature of the coexistence black hole regions for the failure of the equation of *** at these coexistence states,in this work,we develop a general approach by introducing two new ratio *** first one is the ratio of the horizon radii of the saturated coexistence small and large black holes,and the second one measures that of the small black hole molecule number to the total molecule *** demonstrate that the first parameter can serve as an order parameter to characterize the first-order phase *** study also shows that the black hole state in the coexistence region is uniquely determined by these two introduced parameters bounded between 0 and *** results are quite significant in the analytical study of phase transition and the microscopic nature of black hole in the coexistence regions.

关键词： transition. state. thermodynamic

Impact of Carbon Chain Structures in the Backbone on the Flexibility of Modified Polyarylene Sulfide Resins: Molecular Dynamics Simulations and Mesoscopic Analysis

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Chinese Journal of Polymer Science 2024年第4期42卷 544-557页

作者： Chi Zhang Rong liu Jing-Yuan liu wen-Wei Jiang Key Laboratory of Fine Chemical Engineering and Functional Materials School of Chemical EngineeringSichuan UniversityChengdu610065China

In the domain of high-performance engineering polymers, the enhancement of mechanical flexibility in poly(phenylene sulfide) (PPS) resins has long posed a significant challenge. A novel molecular structure, designated as PP-He-IS, wherein imide rings and an aliphatic hexylene chain are covalently incorporated into the PPS backbone to enhance its flexibility, is introduced in this study. Molecular dynamics (MD) simulations are employed to systematically explore the effects of diversifying the backbone chain structures by substituting phenyl units with alkyl chains of varying lengths, referred to as PP-A-IS where “A” signifies the distinct intermediary alkyl chain configurations. Computational analyses reveal a discernable decrement in the glass transition temperature (Tg) and elastic modulus, counterbalanced by an increment in yield strength as the alkyl chain length is extended. Notably, the PP-He-IS variant is shown to exhibit superior yield strength while simultaneously maintaining reduced elastic modulus and Tg values, positioning it as an advantageous candidate for flexible PPS applications. Mesoscopic analyses further indicate that structures such as PP-He-IS, PP-Pe-IS, and PP-Bu-IS manifest remarkable flexibility, attributable to the presence of freely rotatable carbon-carbon single bonds. Experimental validation confirms that a melting temperature of 504 K which is lower than that of conventional PPS, and lower crystallinity are exhibited by PP-He-IS, thereby affording enhanced processability without compromising inherent thermal stability. Novel insights into the strategic modification of PPS for mechanical flexibility are thus furnished by this study, which also accentuates the pivotal role played by molecular dynamics simulations in spearheading high-throughput investigations in polymer material modifications.

关键词： Molecular dynamics simulations Polyarylene Sulfide Main-chain modifications Flexibility Aliphatic hexylene chain

An Approximation Algorithm Based on Seeding Algorithm for Fuzzy k-Means Problem with Penalties

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Journal of the Operations Research Society of China 2024年第2期12卷 387-409页

作者： wen-Zhao liu Min Li School of Mathematics and Statistics Shandong Normal UniversityJinan 250014ShandongChina

As a classic NP-hard problem in machine learning and computational geometry,the k-means problem aims to partition the given dataset into k clusters according to the minimal squared Euclidean *** from k-means problem and most of its variants,fuzzy k-means problem belongs to the soft clustering problem,where each given data point has relationship to every center *** to fuzzy k-means problem,fuzzy k-means problem with penalties allows that some data points need not be clustered instead of being paid *** this paper,we propose an O(αk In k)-approximation algorithm based on seeding algorithm for fuzzy k-means problem with penalties,whereαinvolves the ratio of the maximal penalty value to the minimal ***,we implement numerical experiments to show the effectiveness of our algorithm.

关键词： Approximation algorithm Seeding algorithm Fuzzy k-means problem with penalties